1. Field of the Invention
The subject invention relates to a diagnostic and medication delivery system having a medication delivery pen, blood monitoring device and a lancer removably mounted in a common housing.
2. Description of Related Art
Home diabetes therapy requires the patient to carry out a prescribed regimen that involves self-testing blood glucose levels and administering an appropriate dose of insulin. Insulin has traditionally been injected by a hypodermic syringe, which suffers from numerous drawbacks. For example, syringes are not preloaded with medication, requiring the user to carry a separate medical vial. Syringes also require a degree of dexterity and sufficient visual acuity on the part of the patient to line up the needle of the syringe with the rubber septum on the medical vial and to ensure that the syringe is loaded with the proper dosage. As a result, unintentional needle pricks commonly occur.
To overcome the drawbacks of syringes, medication delivery pens have been developed, which facilitate the self-administration of medication such as insulin. Such delivery pens use prepackaged insulin and may be used repeatedly until the medication is exhausted. Mechanical and electronic pens are available. Electronic pens incorporate electronic circuitry that sets and/or indicates the appropriate dosage of insulin and stores data for subsequent downloading such as the time, date, amount of medication injected, etc.
In additional to downloading data, the electronic capabilities of such pens can also be used to mechanically simplify the pen and enhance the pen's ease of use. For example, some known pens employ an interlock mechanism to prevent actuation of the injection button when the medication cartridge is not properly connected to the pen so that an overdose does not occur. The interlock mechanism is relatively complex from both a mechanical perspective and a patient perspective. The electronic detection of the presence or absence of a properly connected cartridge can eliminate the need for such an interlock.
Additional mechanical improvements to medication delivery pens are also desirable to increase reliability and ensure that the proper dosage of medication is delivered. For example, known pens must undergo a priming process every time they are loaded with a cartridge. Priming ensures that the drive mechanism is in contact with the piston inside the cartridge so that the full axial travel of the drive mechanism is used to inject medication rather than being used in part to approach and contact the piston. If priming is not properly performed by the user, the actual dosage of medication that is delivered will not equal the desired dosage. Accordingly, there is a need to eliminate or reduce the amount of priming that the user must perform.